Gearing as well as a rotary encoder equipped with such gearing

Abstract

A gear mechanism includes a rotating input element, a rotating output element, and at least one first force transmission device arranged along a spiral line on a face of the input element. A second force transmission device is arranged along an encircling line on a face of the output element. The interaction of these force transmission devices transmits a turning moment from the input element to the output element, whereby this turning moment effects a rotating motion in the output element so that the rotational speed is lower than the rotational speed of the input element. A rotary encoder may be equipped with a gear mechanism of the aforementioned type.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a gearing and to a rotary encoder equipped with such gearing.BACKGROUND INFORMATION[0002]In addition to angle-measuring instruments, which allow an angle measurement at a rotatable shaft in incrementable measuring steps, so-called absolute angle-measuring instruments—also referred to as rotary encoders—are conventional as well. These allow an absolute angle determination within a single shaft rotation. Furthermore, if the number of performed shaft rotations is to be recorded as well, so-called multiturn rotary encoders are generally utilized. With such multiturn rotary encoders, the absolute angular position is determined within one shaft rotation, i.e., between 0° and 360°, via a code disk connected to the shaft, which is scanned with the aid of a suitable photoelectric scanning unit. To obtain the required information regarding the number of effected shaft rotations, a reduction or step-down gear is typically provided, v...

AI Technical Summary

Benefits of technology

The present invention provides a gearing that has small dimensions and can be produced at low cost. The gearing can be used in a rotary encoder and has a high reduction ratio, while keeping the outer diameter of the entire encoder small. The gearing has low mass inertia, which is advantageous for high dynamic changes in rotary motions. The force-transmission arrangement of the gearing includes at least one first force-transmission device and one second force-transmission device, which are arranged along a spiral line and a circular curve, respectively. The gearing and the rotary encoder have improved performance and efficiency.

Problems solved by technology

This design may be disadvantageous insofar as it requires relatively large installation space, in particular as far as the outer dimensions in the radial direction are concerned.

Since the electronic components of rotary encoders are integrated to an ever greater extent and are thus miniaturized as well, the installation space for the mechanical components of these devices often becomes a limiting factor in such miniaturization endeavors.

Furthermore, the installation space required in the axial direction may be comparatively low.

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